As the name says the "Motif of Harmful Sensation" is a trope used in literature, movies or other media about harm - physically or mentally - that is taken by sensing or not sensing a certain object or creature.

Popular examples of this trope are "The Weeping Angels" of the TV-Show "Doctor Who" (who will approach you if you don't keep looking at them), "The Brown Noise/Tone" (a tone frequency that is suppose to make everybody lose control over their bowels if heard) or the Elder Gods of the "Cthulhu Mythos" by H.P. Lovecraft (who can cause instant insanity by just looking at them).